Thermal nitridation passivation dependent band offset and electrical properties of AlOxNy/GaAs gate stacks

Fermi level pinning attributed to oxides at the GaAs/high-k interface is a major obstacle to develop GaAs-based metal-oxide-semiconductor devices with high performance. In this letter, thermal nitridation treatment of GaAs surface prior to the high-k deposition is proposed to solve the issue of interface pinning. Results have confirmed that nitridation passivation effectively suppresses the oxides formation and leads to a shift in the Fermi level toward the conduction band minimum on the GaAs surface, which increases the conduction band offset at the GaAs/AlOxNy interface, followed by a saturated accumulation capacitance with reduced gate leakage current.